The scenario described suggests that medium brown fur provides a survival advantage, while light brown and dark brown fur are less favorable. This scenario is characteristic of disruptive selection, where individuals at both extremes of a trait are favored over the intermediate trait.
In terms of the distribution curve for the mouse population, it would likely depict two peaks at either end of the graph with a dip in the middle, reflecting that both light brown and dark brown mice are more common than medium brown mice.
Thus, the correct response is:
disruptive; two peaks at either end of the graph with a dip in the middle.